Antimony Ammoxidation Catalyst Stabilization via Low-Melting Compound
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Solution Overview
Problem
Current ammoxidation catalysts in the production of acrylonitrile face challenges in maintaining stability and conversion over time, with existing methods providing only minor improvements and being inefficient due to high melting point antimony-containing compounds requiring higher amounts, leading to vaporization and operational issues.
Innovation Solution
The process involves adding an antimony-containing compound with a melting point less than 375°C, such as antimony triacetate, to the antimony ammoxidation catalyst during the ammoxidation process to suppress vaporization and maintain catalyst conversion and selectivity, which can be done in smaller amounts and at lower temperatures, thereby improving stability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high melting point antimony-containing compounds are used to stabilize the catalyst, then catalyst stability is improved, but the amount required increases and vaporization occurs
Solution Approach 1:
The patent changes the melting point parameter of the antimony-containing compound from high (conventional) to low (below 375°C). This parameter change allows the compound to be added in smaller amounts at lower temperatures, reducing vaporization while maintaining catalyst stability through controlled deposition on the catalyst surface.
2Reliability
If high melting point antimony-containing compounds are used, then catalyst stability is improved, but higher amounts are required leading to operational issues
Solution Approach 1:
The patent changes the melting point parameter of the antimony-containing compound to below 375°C, which enables effective stabilization with smaller quantities. The lower melting point allows the compound to deposit on the catalyst at lower temperatures, improving efficiency and reducing operational issues associated with handling and adding large amounts of high-melting-point materials.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively maintains catalyst conversion within 10% of the target over a year and selectivity to acrylonitrile at 50% or higher, significantly improving catalyst stability and reducing operational inefficiencies compared to conventional methods.
Implementation Method 1
adding an effective amount of an antimony-containing compound to the antimony ammoxidation catalyst to maintain catalyst conversion and selectivity... vaporizing the antimony-containing compound to suppress the release of the antimony ammoxidation catalyst vapors
Data Source
AI summary
The present disclosure relates to a process for stabilizing an antimony ammoxidation catalyst in an ammoxidation process. The process may comprise providing an antimony ammoxidation catalyst to a reactor; reacting propylene with ammonia and oxygen in the fluidized bed reactor in the presence of the antimony ammoxidation catalyst to form a crude acrylonitrile product; and adding an effective amount of an antimony-containing compound to the antimony ammoxidation catalyst to maintain catalyst conversion and selectivity; wherein the antimony-containing compound has a melting point less than 375° C. The present disclosure also relates to catalyst compositions and additional processes using the antimony ammoxidation catalyst stabilized by an antimony-containing compound.